Studio 5 3 March 2008

CSE 431S (Spring 2008)

Studio 5: Real grammar, real ambiguities, real fun

Studio Sessions Overview:

We gather as a community in studio session to learn from each other. Our community includes:
- Instructor
- TAs
- Students
Our community is egalitarian in terms of learning: all of us will have questions and all of us should try to provide answers.
The idea is to challenge each other and to share what we discover.
You are free (downright encouraged) to collaborate in this session:
- Primarily within your small group of 2-3 people
- Secondarily with any group in the class
- As much as you like with the instructor and TAs
In studio, the instructor's mission is to observe, interact, and work with groups.
- How you think, work, and arrive at a solution is more important than getting the right answer. Thus, the instructor and TAs will observe you throughout the exercise and offer constructive feedback.
- The help you receive may be incomplete at any given time, so that you can work through more of the solution on your own. Do not hesitate to ask for more help.
In studio, the student's mission is to acquire new knowledge and skills by the collaborative solving of problems.
- You are not graded on whether you get wrong or right answers on this exercise.
- You are graded on your level of participation in studio.
Participation is defined as
- Asking questions, at any level, of any person in the studio
- Discussing possible solutions with people in the studio
- Helping somebody in the studio solve a problem
- Presenting or demonstrating your solution to people in the studio
- Documenting your group's experiences in studio
Please eliminate external stimuli (cell phones, IM, Facebook) during studio. Please devote yourself to learning, mastering, and extending the material for the session.

The results of your studio session are to be reported and documented in a file that you save in your workspace. You are to print and turn in one copy of that report for your group. In the descriptions of the studio exercises, verbs like report and document are indications of activities you should summarize and discuss in your report.
In your groups, take turns documenting results, looking over shoulders, and staffing the keyboard.
It is unacceptable to copy anything without understanding it. At any point, the TA or instructor can point to something you've done and ask you why it works, or change it and ask what would happen with the modification.

In each of the following sections, go as far as you can in the time allotted, but move on to the next section so you'll have a chance to work on each section while in studio.

Warm Up: (10 minutes)

Open up some kind of document you can print later that has your group's findings. In that document be sure to include:
- The title: Studio 5
- Your group's members' names
You will turn in just one document per group.
Open the lab 3 page
Get an instance of Lab3 installed on the computer you and your group are using in Studio.
Run the ant target testClassSolution to make sure you've installed it correctly.
Run the ant target testMySolution and verify that some output is produced.

Main Problems

All of your work will be done in the jmm.cup file. Work carefully, in groups as usual, but feel free to bounce ideas off others around you. For each of the situations below:

Follow the instructions, and document your findings throughout
Determine if grammar became ambiguous
Address the ambiguity (the hard part) by modifying the grammar
Document what you did and why you did it.

[ 35 minutes ] Around line 384 of jmm.cup, you will see the following productions for a SelectionStatement:
```
SelectionStatement
        ::= IF LPAREN Expression RPAREN Statement ELSE Statement
/*      |   IF LPAREN Expression RPAREN Statement
 */
        ;
```
Leave the first production alone, but uncomment the second one, so that both are considered by CUP. Address the resulting ambiguity.

[ 20 minutes ] Below the productions you considered above, Around line 405 of the jmm.cup as originally give to you, you will see the productions for PrimaryExpression:

PrimaryExpression
        ::= QualifiedName:t
        |   NotJustName:rhs
/*
 *  You will eventually have to explain the conflicts that arise when the rule below
 *       is uncommented.
 *  This rule lets a block ( { .... }  ) serve anywhere a primary expression could.
 *  So you could write  a = { while (h>5) h = h -k; };
 *
 *      |   Block:rhs
 */
        ;

Uncomment the last production so it can be considered by CUP. Address the resulting ambiguity.

[ 20 minutes ] Work together on the rest of Lab 3 by constructing and linking in portions of the AST.

Finally

Be sure to submit the following before leaving studio:

A printed copy of your jmm.cup file.
A printed copy of your document with your findings.

You are welcome to use the work done in studio for this portion of your Lab 3 assignment. Just be sure to credit the group for the work done for these parts.

Last modified 11:46:15 CST 03 March 2008 by Ron K. Cytron

CSE 431S (Spring 2008) Studio 5: Real grammar, real ambiguities, real fun

CSE 431S (Spring 2008)

Studio Sessions Overview:

Warm Up: (10 minutes)

Main Problems

Finally

CSE 431S (Spring 2008)

Studio 5: Real grammar, real ambiguities, real fun